Abstract
The relations between the cooling ability and the process of oxidation and polymerization of oil by Indiana method are examined. The cooling ability increases slightly in the induction period of oxidation and polymerization process of oil and becomes progressively rapid in the peroxide formation period up to the maximum at the end of this period. Then it decreases gradually in the peroxide decomposition period and rapidly in the polymerization period.
The variations of other properties are also associated closely with these oxidation process. When the cooling ability becomes the maximum, the peroxide value becomes the maximum and the viscosity and the amount of sludge begin to increase. These variations of cooling ability can be nearly represented by a quadratic equation. The blowing time (τHmax) at which the cooling ability becomes the maximum can be a criterion experessing the life of quenching oils and the radius of curvature (γHmax) of the curve at the maximum cooling a bility can be used as an index representing the degree of the variation of cooling ability resulted from the deterioration of oils.
